Using dilemma cards describing some of the issues affecting Yellowstone National Park, students work in small groups to consider management issues that meet both of the conflicting mandates that the National Park Service must follow. After the investigation, students will be able to answer the question: How does the National Park Service attempt to balance the dueling mandates of preservation and use in complex dilemmas? Background The National Park Service is only one of the federal agencies responsible for managing public lands. Others include the Bureau of Land Management, the U.S. Forest S Duration: 30 Minutes.